#include<cstdio>
#include<cstring>
#include<set>
using namespace std;

typedef int State[9];
const int MAXSTATE = 1000000;
State st[MAXSTATE];
int dist[MAXSTATE];
State goal = {1, 2, 3, 8, 0, 4, 7, 6, 5};

int vis[362880], fact[9];
void init_lookup_table() {
    fact[0] = 1;
    for (int i = 1; i < 9; ++i) fact[i] = fact[i - 1] * i;
}

int try_to_insert(int s) {
    int code = 0;
    for (int i = 0; i < 9; ++i) {
        int cnt = 0;
        for (int j = i + 1; j < 9; ++j) {
        	if (st[s][j] < st[s][i]) ++cnt;
        }
        code += fact[8 - i] * cnt;
    }
    if (vis[code]) return 0;
    return vis[code] = 1;
}

const int dx[] = {-1, 1, 0, 0};
const int dy[] = {0, 0, -1, 1};

int bfs() {
    init_lookup_table();
    int front = 1, rear = 2;
    while (front < rear) {
        State &s = st[front];
        if (memcmp(goal, s, sizeof(s)) == 0) return front;
        int z;
        for (z = 0; z < 9; ++z) if(!s[z]) break;
        int x = z / 3, y = z % 3;
        for (int d = 0; d < 4; ++d) {
            int newx = x + dx[d];
            int newy = y + dy[d];
            int newz = newx * 3 + newy;
            if (newx >= 0 && newx < 3 && newy >= 0 && newy < 3) {
                State &t = st[rear];
                memcpy(&t, &s, sizeof(s));
                t[newz] = s[z];
                t[z] = s[newz];
                dist[rear] = dist[front] + 1;
                if(try_to_insert(rear)) ++rear;
            }
        }
        ++front;
    }
    return 0;
}

int main() {
	char c;
    for (int i = 0; i < 9; ++i) {
    	scanf("%c", &c);
        if (c >= '0' && c <= '9') {
        	st[1][i] = c - '0';
        } else {
        	--i;
        }
    }

    int ans = bfs();
    if (ans > 0) printf("%d\n", dist[ans]);
    else printf("-1\n");
    return 0;
}